 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A potential conflict occurs between 2 air carrier aircraft when a B737-700 loses both packs at FL410 and performs an emergency descent to FL250 on frequency with ZME.
| Attributes | |
| ACN | 639524 |
| Time | |
| Date | 200412 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : stl.vortac |
| State Reference | MO |
| Altitude | msl bound lower : 25000 msl bound upper : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-700 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other other vortac |
| Flight Phase | cruise : level |
| Route In Use | departure sid : n/s |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zme.artcc |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 80 flight time total : 14000 flight time type : 9000 |
| ASRS Report | 639524 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : radar aircraft equipment : tcas other controllera other flight crewa other flight crewb |
| Resolutory Action | controller : issued advisory flight crew : declared emergency flight crew : overcame equipment problem other |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft Airspace Structure |
| Primary Problem | Aircraft |
Narrative:
At top of climb 100 mi southeast of st louis at FL410, we had a left bleed trip. We went through the checklist and accomplished procedures, resetting the bleed trip. For the next 3-5 mins at cruise, we talked about the 'what ifs' of if the bleed trip did not reset or if both tripped. During this discussion, the left bleed and right bleed tripped. We immediately donned our emergency oxygen masks, established communications and confirmed that the cabin altitude was climbing. We declared an emergency and accomplished an 'emergency descent.' during the descent, center called out traffic and asked if we could level off at FL350, at which time we got a TA from TCASII. We completed descent to FL250. During the descent we were able to reset the bleeds. Cabin altitude never got above approximately 8000 ft. We continued on to mco at FL250.
Original NASA ASRS Text
Title: A POTENTIAL CONFLICT OCCURS BTWN 2 ACR ACFT WHEN A B737-700 LOSES BOTH PACKS AT FL410 AND PERFORMS AN EMER DSCNT TO FL250 ON FREQ WITH ZME.
Narrative: AT TOP OF CLB 100 MI SE OF ST LOUIS AT FL410, WE HAD A L BLEED TRIP. WE WENT THROUGH THE CHKLIST AND ACCOMPLISHED PROCS, RESETTING THE BLEED TRIP. FOR THE NEXT 3-5 MINS AT CRUISE, WE TALKED ABOUT THE 'WHAT IFS' OF IF THE BLEED TRIP DID NOT RESET OR IF BOTH TRIPPED. DURING THIS DISCUSSION, THE L BLEED AND R BLEED TRIPPED. WE IMMEDIATELY DONNED OUR EMER OXYGEN MASKS, ESTABLISHED COMS AND CONFIRMED THAT THE CABIN ALT WAS CLBING. WE DECLARED AN EMER AND ACCOMPLISHED AN 'EMER DSCNT.' DURING THE DSCNT, CTR CALLED OUT TFC AND ASKED IF WE COULD LEVEL OFF AT FL350, AT WHICH TIME WE GOT A TA FROM TCASII. WE COMPLETED DSCNT TO FL250. DURING THE DSCNT WE WERE ABLE TO RESET THE BLEEDS. CABIN ALT NEVER GOT ABOVE APPROX 8000 FT. WE CONTINUED ON TO MCO AT FL250.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.